1. Field of the Invention
This invention relates to the field of computers, and in particular to the field of computer games, simulations, and robotic control.
2. Description of Related Art
Users interact and control computer games and simulations via a variety of user interfaces. A common user interface is via a joystick with one or more buttons or triggers. The user controls the simulated movement of a game piece, such as an animated figure on a computer screen, by tilting the joystick in the direction that the user desires the game piece to move. Similarly, a user controls the simulated flight of an aircraft by tilting the joystick corresponding to the movement of controls on an actual aircraft. The joystick is also commonly used as an input device for remotely controlled equipment, such as model airplanes, factory traveling lifts, and the like. As the field of robotics continues to expand, more devices and equipment will be remotely controlled, predominantly via a computer interface between the user and the device being controlled.
Another common computer interface device is a mouse. Although a mouse is convenient for interacting with computer applications such as word processors and spreadsheets, its use as an interface device for games, simulations, and remote control is somewhat limited. Conventionally, the mouse is used to select from a menu of options to control the device. For example, the user may point to an animation of a control that is displayed on a screen, and click at differing locations on the control to effect different motions. In a game or simulation, the user may click on an animated figure and drag the figure to a new location, but such an instantaneous translation may be inconsistent with a sense of lifelike movement that most games and simulations strive to achieve. Touchpads and directional arrows on a keyboard are also commonly used, with similar interface characteristics as a mouse.
The user interface to a computer game or simulation is particularly problematic with regard to the control of figures and objects that can be moved independently. Traditionally, a single motion vector is associated with the user interface control. The user controls, for example, a simulated ping-pong paddle, and the motion of the simulated ping-pong ball is controlled directly by the motion or position of the ping-pong paddle. Similarly, a user controls the motion of a simulated aircraft, and controls the trajectory of a simulated projectile from the aircraft by appropriately orienting the simulated aircraft and then triggering the discharge of this projectile at this orientation. Some actual games or events, however, do not conform to this simulated paradigm. A football player does not necessarily pass the football in the same direction that he is traveling. A pilot can fire a guided missile in a direction that is different from the direction that the aircraft is traveling. Computer games and simulations must support the independent motion control of figures and objects if they are to convey a representation that is lifelike. In a conventional computer game or simulation, independent motion control is effected via a context switch. For example, dual controls are provided, either as two discrete joysticks, for example, or two discrete controls displayed on the computer screen. One of the joysticks or controls is used to control, for example, the motion of the football player, while the other is used to control the passing of the football. If only one joystick or control is available, the user effects the independent control via another switch that controls the interpretation of the input received via the single joystick or control. This explicit context switch, or the switch to a second control area on the screen, can be a disconcerting distraction that interferes with the intended simulation of lifelike behavior.